Question

JAVA

Question 1

When implementing a method, use the class’s set and get methods to access the class’s ________ data.

a. public.

b. private.

c. protected.

d. All of the above.

Question 2

Set methods are also commonly called ________ methods and get methods are also commonly called ________ methods.

a. query, mutator.

b. accessor, mutator.

c. mutator, accessor.

d. query, accessor.

Question 3

Composition is sometimes referred to as a(n) ________.

a. is-a relationship

b. has-a relationship

c. many-to-one relationship

d. one-to-many relationship

Question 4

Instance variables declared final do not or cannot:

a. Cause syntax errors if used as a left-hand value.

b. Be initialized.

c. Be modified after they are initialized.

d. None of the above.

Question 5

Inheritance is also known as the

a. knows-a relationship.

b. has-a relationship.

c. uses-a relationship.

d. is-a relationship.

Question 6

Which of the following is not a superclass/subclass relationship?

a. Employee/Hourly Employee.

b. Vehicle/Car.

c. Sailboat/Tugboat.

d. None of the above.

Answer 1

1) All of the above

set and get method are basically introduced to have private members in place and could be accessed only via object to that class. Hence we can say when we talk about get and set methods they provide access to private data but there is no restriction that only private data can have get, set method even other members public and protected as well.

2) mutator, accessors

Set methods are also called mutators (derived from word mutate which means to become different).Set methods set the value of variable hence making change to variables.

Get methods are also called accessors. These are used to return the value of variable and hence we are able to access the value that's why called accessors.

3) has-a

Composition is done by having an instance of another class. When you don't want to have all the properties inherited of some other class instead wants to have the class instance then you can make instance of that class as a field.

4) Be modified after they are initialized

Final variables are like constant whose value cannot be changed once assigned.

5) is-a relationship.

Inheritance is also known as is-a relationship. When we inherit some class to another class then subclass becomes of base class type. Car inherits Vehicle or we can say Car is-a Vehicle.

6) Sailboat/Tugboat

Sailboat and Tugboat both are type of boat so they don't make a superclass/subclass relationship with each other.